Thursday, September 5, 2013

The Wright Brothers Stood on Cayley's Shoulders

Sir Isaac Newton famously expressed that in order to make his numerous contributions to science, he stood on the shoulders of giants.  This seems to be a modest claim given the huge individual leaps of intellect he made.  A book that I recently read, "The Man who Discovered Flight: George Cayley and the First Airplane," by Richard Dee, had me thinking about the notion of how we are always continuing the work of our predecessors.

When any of us think about the first airplane, we invariably think of the Wright Brothers and their historic achievement; few have ever even heard of George Cayley.  Cayley's contributions to aviation were numerous, but they preceded the Wright Brothers' flight by about a century.  Consider this excerpt from Dee's book:

"Within the course of six scribbled pages in his notebook, Cayley had shown that man-made flight by wing was a theoretical possibility, but practically, with engineering constraints as they were at the time, it was a non-starter.  So having discovered that it could happen and then almost immediately proving that it couldn't happen yet, what next?"

Cayley discovered that an inclined plane that translates horizontally experiences an upward vertical force through atmospheric interaction around the year 1800.  The young engineer with a passion for aeronautics had stumbled upon the lift force, and spent the remainder of his life trying to deliver upon its promise.

He realized that it was to be a very difficult challenge to build a device that would let man fly without being lighter than air.  There were two principal challenges.  The first was making the airplane light enough so that the lift force would be sufficient to overcome gravity.  The second, which was only really solved in the early twentieth century with the advent of low-speed propellers, was how to give the airplane thrust.

Cayley realized that truly sustained flight required some sort of lightweight motor and could not foresee one in his lifetime.  As such, Cayley's best practical effort in aviation occurred in 1853, when a boy was carried perhaps one hundred yards by his glider.  This very important flight was not well documented, so details such as its date and the distance traveled remain murky.

In truth, Cayley's most significant contributions to aviation are in its theory rather than its practice.  After discovering lift, he aimed to optimize it.  He studied nature's animals that coast through fluids, namely birds and fish.  He noted their geometry for guidance on wing design.  He made a few significant publications on how to best design an airplane; to be fair, they contained as many poor guidelines as they did brilliant ones, but this is to be expected when doing any kind of pioneering work.

I actually do not recommend "The Man who Discovered Flight" to readers.  I wanted to get into the mind of George Cayley, and while some parts allow for this, they are few and they are interspersed between long sections about his family and his political undertakings.  The highlights of the book are the many engineering sketches copied from Cayley's various notebooks.  They give insight to the obsession Cayley had with flight and his desperation to make this dream a reality in his lifetime.

The principal thing that I take away from the story of George Cayley is that any work in the realm of science and engineering has a heritage, and it is easy to fly right by it without noticing.

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